More than 9,000 criminals had their prison sentence suspended last year despite having more than 15 previous convictions or cautions, criminal justice campaigners have revealed.

The Centre for Crime Prevention (CCP) has called for suspended sentences to be abolished after figures obtained under the Freedom of Information Act showed the punishment was being repeatedly handed out to serial offenders.

A total of 9,052 offenders had prison sentences suspended in 2012/13 despite 15 or more previous conviction or cautions, while 11,670 offenders with more than 10 previous convictions or cautions received suspended jail sentences.

CCP's research also shows almost one in three - or 31% - of prison sentences were suspended in 2012, up from 2% in 2002.

And among them 7,288 suspended prison sentences were handed to criminals convicted of violence against the person, a 14-fold increase from 504 in 2002, while 488 suspended sentences were given to sex offenders, eight times higher than the 58 passed a decade earlier.

The report cites changes in Victoria, in Australia, where suspended sentences for all offences will vanish from courts by September under new legislation.

CCP's figures come at a time of fierce debate over tougher sentences.

Knife crime has split the coalition, as Deputy Prime Minister Nick Clegg said he would block proposals from Justice Secretary Chris Grayling for an automatic jail sentence for anyone caught in possession of a knife on two occasions.

Sentences for banned drivers who cause death on the roads or criminals who kill police or prison officers in the course of duty are to be strengthened, while violent criminals will lose their right to automatic early release from prison.

CCP director Peter Cuthbertson said: "Thugs and sex offenders who think they are finally going to prison are overjoyed when they find out that their prison sentence has been suspended.

"It makes a mockery of justice for victims and puts the public at great risk.

"These figures show that criminals given suspended sentences go on to commit hundreds of thousands of crimes.

There were 110,745 cases of criminals sentenced last year despite one or more previous suspended sentences, according to the figures, including 215 examples of criminals being found guilty despite 10 or more suspended sentences.

A regional sample shows Hertfordshire recorded the greatest increase in the number of criminals whose prison sentences were suspended, from 10 in 2002 to 821 in 2012.

Bedfordshire was second to Hertfordshire with 10 suspended sentences in 2002, rising to 346 in 2012, while Cambridgeshire was third with 20, increasing to 678.

Justice Minister Jeremy Wright said: "Since 2010 criminals are more likely to go to prison - and for longer.

"In the 12 months to June 2013 almost 48,000 offenders didn't 'walk free' but went straight to prison - four times as many as got a suspended sentence.

"It is right that the most serious offenders spend longer behind bars, which is why we are overhauling sentencing and making sure judges have tough sentencing options available to them.

"But sentencing in individual cases is a matter for the independent judiciary based on the full facts of each case."

Shadow Justice Secretary Sadiq Khan said: "These are worrying reports. The public need urgent reassurances from ministers that this isn't justice on the cheap. Suspended sentences being handed out wrongly for serious, violent and repeat criminals would be an insult to victims.

"In the last week, serious questions have been raised about whether open prisons and release on licence have been used inappropriately for serious and violent criminals. We can't afford for public confidence in our justice system to be undermined by the actions of this Government."